JPH04106751U - Automatic inspection device for defects on the circumferential side of cylindrical objects such as nuclear fuel pellets - Google Patents

Abstract

(57) [Summary] [Purpose] This is a device that automatically inspects whether or not there are defects on the circumferential side of a cylindrical object such as a nuclear fuel pellet. To detect the presence of a defective part without erroneously recognizing it even if the axis changes vertically and horizontally. [Structure] A cylindrical body A is rotated about its axis by an autorotation device 3, and a parallel light beam L is incident on an irradiation curved surface S from a projector 1 toward a circumferential side surface A' of the cylindrical body A. As a result, the one-dimensional light-receiving element 2 provided on the side of the irradiation curved surface S has its light-receiving axis Y' aligned with an imaginary line Y that is substantially orthogonal to the parallel light beam L and passes through the axis of the cylindrical body A. Even if the cylindrical body A moves vertically or horizontally in the figure, the relative positional relationship between the parallel light beam L and the irradiation curved surface S remains unchanged. As long as there is no unwanted fluctuation of the cylindrical body, there will be no light reception noise to the one-dimensional light receiving element 2.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is suitable for nuclear fuel rods for pressurized water reactors (PWR) and boiling water reactors (BWR). Regarding the cylindrical bodies such as nuclear fuel pellets that are stored and used in the cladding tube, Automatically removes defects caused by chips, cracks, and adhesion of foreign substances on the peripheral surface. This invention relates to an inspection device that is capable of detecting objects.

0002

[Conventional technology]

As a means of detecting defects on the circumferential side of this type of cylindrical body (including columns and cylinders), , image processing using uniform light beams or diffused light beams has been considered; In some cases, it is difficult to distinguish between defective areas and normal areas. Unable to set threshold. Therefore, as shown in Fig. 4, the detection means actually used in the past has a cylindrical The body a is rotated about the axis b in the direction of the arrow c by an appropriate means, and The cylindrical body a is advanced along the axis b (in the front-rear direction of the drawing), while at this time the cylindrical body A light receiving detector e made of a photoelectric element or the like is arranged on the radial line d of the shaped body a, and further An incident light beam f from a projector (not shown) is irradiated to the intersection point g with the meridian d. However, in this case, the incident ray f is at a predetermined angle θ with the tangent h at the intersection point g. The beams are incident obliquely, so there must be a defect on the circumferential side of the cylindrical body a. For example, in Figure (a), the reflected light beam is directed in the f' direction, and the light receiving detector e receives the reflected light beam. Only when there is a defective part, the abnormal reflected light from there will be detected by the light receiving detector. It is designed to be detected by e.

0003 According to the detection means, since the cylindrical body a advances while rotating, the incident light beam f The spot is scanned in a spiral pattern on the circumferential side of the cylindrical body a, and the entire area of the same side is scanned in a spiral manner. The inspection will be carried out over a period of time, but in this case, using the same method, ( As shown in b), if the axis b shifts even slightly to b', For example, the irradiation point of the incident ray f is not g but g', and the reflected ray is directed to f''. This may cause the light to be received by the light receiving detector e as noise. Become.

0004 As a result, the relative positions of the cylindrical body a, the light receiving detector e, and the incident light beam f vary considerably. High precision adjustment is required, and it is necessary to devote time and effort to the adjustment operation. Not only that, but in reality, when the cylindrical body a rotates on its axis, its center of rotation does not change at all. Since it is difficult to create a high-quality configuration, the so-called S/N ratio between signal and noise also decreases. It will end up being put away.

[0005] Also, as clearly stated in Utility Model Application Publication No. 57-57339 and Japanese Patent Application Publication No. 54-108687, The light from the irradiation light source is turned into a spot light on the surface of the cylindrical member to be inspected. irradiate it, receive the reflected light with a light-receiving element, and try to analyze it with a detection circuit. Similar to the conventional example above, this type of thing also depends on the rotation of a cylindrical body. If the center shifts, correct inspection will not be possible.

[0006]

[Problem that the idea aims to solve]

The present invention was studied in view of the above-mentioned difficulties, and claim 1 of the invention is A one-dimensional photodetector that is sensitive only to light rays incident along the light receiving axis. In addition, the irradiation curve on the circumferential side of the cylindrical object to be inspected is By making the parallel rays of surface illumination orthogonal to the light receiving axis of the primary light receiving element, a circular It is possible to suppress the generation of noise due to the displacement of the axis of the columnar body, and it is easy to adjust. The purpose is to obtain highly reliable test results.

[0007] Further, in claim 2, in addition to the invention of claim 1, a rotation device of a cylindrical body is provided. The installation shall consist of an appropriately arranged conveyor belt and a positioning guide plate. Then, the cylindrical body is made to rotate and advance in such a way that axial runout is unlikely to occur. It further improves the S/N ratio and improves the inspection efficiency of cylindrical objects. I am trying to do.

[0008]

[Means to solve the problem]

In order to achieve the above object, the present invention includes nuclear fuel pellets, etc. in claim 1. A rotation device configured to rotate a cylindrical body in a desired direction around an axis. and within a predetermined area toward the circumferential side of the cylindrical body rotated by the rotation device. a projector that irradiates a parallel beam of light onto the curved surface of the cylindrical body irradiated with the parallel beam of light; and substantially perpendicular to the parallel rays and substantially passing through the axis of the cylindrical body. It consists of a one-dimensional light-receiving element arranged so that the light-receiving axis substantially coincides with the imaginary line. We present an automatic inspection device for defects on the circumferential side of cylindrical objects such as nuclear fuel pellets, which is characterized by: This is what we are trying to provide.

[0009] According to claim 2, the rotation device according to claim 1 includes a cylindrical body mounted thereon and a projector. The transport bell is moved toward the side and tilted so that the projector side is on top. and a rotating sliding contact with the cylindrical body arranged intersecting with the carrying surface of the conveyor belt. It consists of a positioning guide plate with a surface, and the guide plate has a rotational sliding contact. The belt is arranged so that its surface is obliquely arranged in plan view with the transfer direction of the conveyor belt. Its content is that it is placed above the list.

0010

[Effect]

In the case of claim 1, the parallel light beam from the projector is a rotating cylindrical circumferential surface. The reflected light is reflected by an imaginary line passing through the axis of the cylindrical body. The one-dimensional light-receiving element will only receive the light if it matches, so the cylinder Even if the object moves in the same direction as the virtual line, the above parallel rays Since the relative positional relationship between However, if there is a defect in the cylindrical body, light will not be able to enter.

[0011] Also, even if the cylindrical body moves in a direction perpendicular to the above virtual line, the front As in the above, the relative positional relationship between the parallel rays and the irradiation curved surface remains unchanged, so this Even in cases where the The depression will be detected.

0012 According to claim 2, the conveyor belt operates as an inclined body in a predetermined transition direction. , and since it is in contact with the positioning guide, the rotational position of the cylindrical body is in the normal state. In addition to being held, the positioning guide and the transport belt are at an angle to each other. Since the cylindrical body is in an intersection state, the cylindrical body is moved toward the axis of the cylindrical body while rotating. As a result, the cylindrical body is inspected for defects over its entire circumference, and the final As the material is separated from the conveyor belt, subsequent processing becomes easier. .

[0013]

【Example】

The present invention will be described in detail with reference to FIGS. 1 to 3. The projector 1 and the one-dimensional light receiving element 2 and and a rotation device 3, and the projector 1 is located within a predetermined area and emits parallel light rays L. At this time, the type of the light beam L depends on the characteristics of the one-dimensional light receiving element 2, which will be described later. Emissions from tungsten filament bulbs, fluorescent lights, if compatible. Light emission, laser light, strobe light, infrared light, ultraviolet light, etc. can be used. In the invention of claim 1, a cylindrical body A such as a nuclear fuel pellet is arranged such that its axis B is It is rotated by an appropriate rotation device 3 that can rotate it to the right or left so that it is centered. On the circumferential side surface A' of the cylindrical body A, the above-mentioned projector 1 A parallel light beam L is irradiated from the surface, thereby obtaining an irradiation curved surface S as shown in FIG. 1(b). make it possible to do so.

[0014] The one-dimensional light-receiving element 2 has a light-receiving axis Y' that is parallel to the parallel light beam L. substantially perpendicular to the imaginary line Y passing through the axis of the cylindrical body A; It is arranged so that Here, in the one-dimensional light-receiving element 2, the parallel light beam L is a circumferential surface A′ of the cylindrical body A. When the reflected light is reflected from the irradiation curved surface S at It has the property of being able to receive this reflected light when it matches qualitatively, Therefore, in the state shown in FIGS. 1 and 2, this cylindrical body A moves in the direction of the virtual line Y, that is, , even if it actually shifts upward, the relationship between the parallel ray L and the irradiation curved surface S is Since the relative relationship remains unchanged, there is no defect W as shown in FIG. 1(c) on the circumferential surface A'. Unless otherwise specified, no light enters the one-dimensional light receiving element 2 as a source of noise.

[0015] Also, as shown in Figure 2, the cylindrical body A is in the X-ray direction perpendicular to the virtual line Y, actually to the left. In this case, the relative position between the parallel ray L and the irradiation curved surface S The relationship remains unchanged, so the reflected light only has a positional shift to the left and right as a whole. In this case, the direction of reflection is parallel movement, and as a result, no noise is generated.

[0016] Next, the rotation device 3 according to claim 2 is provided with the cylindrical body A placed thereon and directed toward the projector 1. At the same time, the transport bench is tilted so that the projector 1 side is on top. A belt 3a and a cylinder arranged at right angles to the mounting surface 3b of the belt 3a. It consists of a positioning guide plate 3d having a rotational sliding contact surface 3c with the shaped body A. The guide plate 3d is disposed above the conveyor belt 3a. 3, the rotating sliding contact surface 3c of the positioning guide plate 3d and the conveying belt 3 It is arranged so that it is not orthogonal to the transition direction D of a, but obliquely in plan view.

[0017] Therefore, according to the above device, the conveyor belt 3a is connected to a power source (not shown) and a transmission mechanism (not shown). When the columnar body A on the mounting surface 3b moves in the direction of the arrow E, The belt 3a rotates, but since the belt 3a is tilted, the positioning guide plate 3d is positioned at a rotational position in contact with the rotational sliding contact surface 3c of the In other words, it moves in the direction of the axis B of the cylindrical body A, in other words, in the direction along the rotating sliding contact surface 3c. Therefore, the cylindrical body A is inspected for defects over its entire circumference. After the transport belt 3a is removed, the transport belt 3a (not shown) is removed. is installed next to this to transport the inspected cylindrical body to the desired location, or to receive the one-dimensional object. The light reception signal from the optical element 2 causes a predetermined sorting actuator to respond, thereby It is also possible to automate the removal of cylindrical bodies with defective parts.

[0018]

[Effect of the idea]

Since the present invention is constructed as described above, according to claim 1, , when the cylindrical body is a nuclear fuel pellet, the work is much easier than visual inspection of defective parts. This will prevent people from being exposed to radiation, and there will be no inspection errors due to human fatigue. This not only makes it possible to standardize judgment criteria, but also makes it easier to inspect cylindrical objects. There is no risk of noise generation and high accuracy with excellent S/N ratio. Inspection can be guaranteed with simple adjustment operations.

[0019] Furthermore, according to claim 2, the rotation of the cylindrical body is caused by the rotation of the slanted conveyor belt. Due to the drive and placement of the positioning guide plate, this can be done without causing any fluctuation in the axis center line. As a result, more reliable test results can be obtained, and the Due to the diagonal arrangement of the side plate and the above-mentioned belt, the cylindrical body can be moved smoothly and inspected. It is convenient for automating the processing of already finished cylindrical objects, and provides efficient equipment at low cost. be able to.

[Brief explanation of drawings]

FIG. 1 (a) is a front explanatory view of the inspection device according to claim 1, and (b) and (c) are plan views showing the mode of irradiation of a cylindrical object by the same device, with and without defects, respectively.

FIG. 2 is an explanatory front view of the inspection device according to claim 2.

FIG. 3 is a plan view of the device of FIG. 2 with the one-dimensional light receiving element removed.

FIG. 4 shows a conventional circumferential side defect inspection means for a cylindrical body, in which (a) is a normally adjusted state and (b) is an incorrectly adjusted state.

[Explanation of symbols]

1 Floodlight 2 One-dimensional light receiving element 3 Rotation device 3a Transport belt 3b Placement surface 3c Rotating sliding contact surface 3d positioning guide plate A cylindrical body A' Circumferential side B Axial center line D Transition direction L parallel rays S Irradiation curved surface Y virtual line Y' Receiving axis center line

Claims (2)

[Scope of utility model registration request] Claim 1: A rotation device configured to rotate a cylindrical body such as a nuclear fuel pellet in a desired direction around an axis; A projector that irradiates parallel light within a predetermined area, and a projector that is located on the curved surface side of the cylindrical body irradiated by the parallel rays, and that is substantially orthogonal to the parallel rays so as to substantially align the axis of the cylindrical body. 1. An automatic inspection device for defects on the circumferential side of a cylindrical object such as a nuclear fuel pellet, comprising a one-dimensional light-receiving element arranged so that its light-receiving axis substantially coincides with an imaginary line passing through the imaginary line. 2. A rotation device configured to rotate a cylindrical body such as a nuclear fuel pellet in a desired direction around an axis, and a rotating device configured to rotate a cylindrical body such as a nuclear fuel pellet in a desired direction; A projector that irradiates parallel light within a predetermined area, and a projector that is located on the curved surface side of the cylindrical body irradiated by the parallel rays, and that is substantially orthogonal to the parallel rays so as to substantially align the axis of the cylindrical body. a one-dimensional light-receiving element arranged such that a light-receiving axis substantially coincides with an imaginary line passing through the cylindrical body, and the rotation device places the cylindrical body and moves it toward the projector side. a conveyance belt tilted so that the projector side faces upward; and a positioning guide plate arranged intersecting the mounting surface of the conveyance belt and having a rotational sliding contact surface with the cylindrical body. , and the guide plate is arranged above the conveyor belt so that its rotating sliding contact surface is obliquely arranged in a plan view with respect to the moving direction of the conveyor belt. This is an automatic inspection device for defects on the circumferential side of cylindrical objects such as nuclear fuel pellets.